Mathew Martoma has one last chance Monday to convince a jury he’s an innocent man.

If not, the 39-year old former portfolio manager for Steve Cohen’s SAC Capital Advisors Capital could go to prison until he’s 54.

Martoma stands accused of engineering the most lucrative insider-trading stock deal ever — ringing up $276 million in profits and averted losses in Elan and Wyeth shares based on illegal tips.

Prosecutors allege Martoma got tipped to unsuccessful drug trials days before the results were revealed and then quickly called Cohen with the hot news. The hedge fund then systematically unloaded — and then shorted — the stocks.

With closing arguments in the four-week trial scheduled for Monday, the defense team is hoping to convince the Manhattan federal court jury that news that the drug trials were not that impressive was widely known and that SAC had many other sources to short those stocks.

Martoma’s fate all hinges on what jurors believe happened during a six-week period in the summer of 2008.

The drama got started on June 17, when Elan and Wyeth put out a press release announcing “encouraging top-line results” from its phase 2 clinical trial of Bapineuzumab, the drug it was testing for Alzheimer’s disease.

The companies promised to release full results on July 29, at the International Conference on Alzheimer’s Disease. But they also said “further analysis” will continue in advance of the conference, giving investors hope that more good news was coming.

Both Elan and Wyeth stock jumped on the June 17 release. Elan — whose earnings were more exposed to the new miracle drug — gained 3 percent to close at $30.

The stocks of both continued to gain steam over the next few weeks, with Elan adding 20 percent to peak at $36 on July 10. The broader markets were falling at the time so investors, generally, were feeling optimistic about the drug trials.

Martoma’s defense, however, told the jury that by mid-July some analysts were questioning whether the drug stocks had gotten overheated given the uncertainties about the drug.

But Martoma had predicted Elan stock would go to $50, and remained bullish at that time, prosecutors said. Martoma’s bullishness was supported by his inside source, Dr. Sidney Gilman, the famed neurologist on the safety monitoring committee, who had been chosen to give the final results on July 29.

On July 17, Gilman received those final results from Elan in a confidential PowerPoint presentation and quickly emailed Martoma. The two spoke for an hour and 45 minutes, after which Martoma booked a trip to Detroit for Saturday.

That evening, he called Gilman back, said he would be in the area and wanted to drop by.

Martoma flew to Detroit on July 19, took a taxi to Gilman’s office at the University of Michigan Medical Center to personally eyeball the charts of the study’s results. What he saw would rock his world, prosecutors allege.

The drug wasn’t as promising as Wall Street — and he — anticipated. In light of the less-than-stellar drug trail results, Martoma’s bullish stance on the two drugs meant SAC could lose millions based on its $700 million position in Elan and Wyeth, according to prosecutors.

The next day, July 20, was a Sunday. Martoma emailed his boss, Steve Cohen, with the urgent message: “Is there a good time to catch up with you this morning? It’s important.” They spoke on the phone for 20 minutes.

The next day SAC started unloading its entire position in both stocks through “dark pools” to disguise the seller’s identity. SAC also shorted the stocks. Elan shares fell nearly 9 percent in a week — from $35 on July 21 when SAC started to sell, to $31.90 on July 28.

On July 29, after the market closed, Gilman released the final drug results at ICAD. Instead of showing additional promising news, the full results were “similar in substance” to the June 17 press release, Dr. Thomas Wisnieski, an NYU neurologist for the defense, testified last week.

To Martoma’s lawyers, the similarity of the two means that even if Martoma did receive the full results ahead of time, they were not “non-public material information” required for an insider trading crime because the information, being so similar to the June 17 press release, was already public.

What wasn’t public was that the report wouldn’t offer the details investors were expecting.

Over the next days, both stocks were crushed. Elan shares fell the most, cratering 42 percent to $19.63, over that span.

Martoma’s legal team, in its closing arguments Monday, will have to have the jury believe its version of events as to why that drop happened — or Martoma’s toast.